Mechanical pencil



C E WEHN MECHANICAL PENCIL Flled July 6 1946 Feb 1, 1949 Patented Feb.I, 1949 UNITED STATS FFICE 6 Claims. (Cl. 12018) This invention relatesto mechanical pencils, and especially to improvements in the propellingmechanism whereby the lead is advanced.

The object of the present invention is generally to improve and simplifythe construction and.

operations of pencils of the mechanical type; to provide a mechanicalpencil in which the number of parts employed is reduced to a minimum; toprovide amechanical pencil which consists of a barrel section, a pointor lead-carrying section, and a propelling mechanism for advancing thelead as it wears away; to provide a propelling mechanism which may beassembled as a complete unit before it is inserted in the barrel; toprovide a novel form of anchor mechanism whereby the propellingmechanism is permanently secured after insertion in the barrel; andfurther, to provide means for imposin a constant frictional resistanceon the propelling mechanism to take up Wear and to prevent accidentalrotation of the propelling mechanism.

The mechanical pencil is shown by way of illustration in theaccompanying drawings in which:

Fig. 1 is a central vertical longitudinal section of the pencil;

Fig. 2 is a side elevation of the propelling unit as it appears beforebeing inserted in the barrel; and

Fig. 3 is a cross-section taken on line III-III of Fig. 1. p

Referring to the drawings in detail, and particularly Figs. 1 and 2, Aindicates the point or lead-receiving end of the pencil, B the barrel,and C the propelling or lead-advancin mechanism. The point end is of theusual construction, that is it has a lead-receiving passage 2 formedtherein for the reception of a lead 3 which may be inserted from thepoint or front end or from the rear end of the passage. The point isprovided with a threaded extension 4 which screws into the front end ofthe barrel to permit removal of the point when inserting the lead fromthe rear. 7

The barrel is cylindrical-shaped in cross section and may be as long asdesired. It is threaded internally at the front end to receive thethreaded extension of the point A and is otherwise provided with apropeller rod guide and a plurality of keyways 6, the function of whichwill hereinafter he described.

The propelling mechanism consists of a nut having a rearwardly extendingtubular portion 8 with a reduced end 9, a shoulder ill being formedbetween the main tubular portion and the reduced end 9. Extendingthrough-the nut and the tubular extension is a threaded rod H and formedintegral therewith is a pusher rod I2 which extends through the guide 5and into the lead-receiving passage 2 to engage the lead 3. The rod isflattened as at M and the flattened portion is extended to one side toform a key l5 which extends into one or another of the keyways 8 formedin the inner surface of the barrel. This key secures the rods 5 i' andit against rotation with relation to the barrel and pencil point, but.

permits free longitudinal movement of the rods.

Secured in the rear end of the barrel is a collar it through which thereduced end 9 of the tubular member 8 extends. The shoulder I0 abuts theinner face of the collar and a cap I! abuts the outer face of thecollar. The collar will hereinafter be referred to as an anchor memberas it is pressed in and permanently secured when inserted in the end ofthe barrel. The cap I1 is similarly pressed on and is permanentlysecured on the reduced end 9 of the tubular member, hence the reducedend of the tubular member also functions as an anchor member. The cap l7serves the function of a rotor. That is, by holding the barrel androtating the cap, tube 8 and nut 1 are rotated and as the threaded rod Il is held against rotation by the key E5, the pusher rod I2 will beeither advanced or retracted depending upon whether the cap is rotatedin one direction or the other.

In actual practice it is possible when applying and securing the cap llthat a frictional contact is made between the inner end of the cap andthe collar, and similarly between the shoulder Ill and the collar, butsuch frictional contact would soon wear away and the cap and the nutactuated thereby might rotate so freely as to cause accidental advanceor retraction of the pusher rod and lead. To avoid this and at the sametime make it possible to take up wear, an annular recess I8 is formed inthe collar 56 and a small helical compression spring i9 is insertedtherein.

This spring pushes against the inner end of the cap and thus holds theshoulder H} in frictional contact with the collar it, the friction beingjust sufficient to resist rotation of the cap accidentally. Also, aswear takes place, the spring extends and the friction imposed remainssubstantially constant.

The pencil as a whole consists of a minimum number of parts which aresimple tomanufacture and assemble. The parts forming the propeller unitmay be assembled durin manufacture as shown in Fig. 2, and then byinserting this unit into the barrel and pressing the collar 56 intoplace, assembly is completed and all parts are permanently held againstremoval from the barrel by the two anchor members, to wit the collar l6against which the shoulder l6 abuts and the reduced end 9 on which thecap is pressed and secured.

The only metallic parts required are the thread-- such as the cap, thebarrel and the point may be made of a suitable plastic or similarmaterial, and while this and other features of the invention have beenmore or less specifically described and illustrated, it should beunderstood that changes may be resorted to within the scope of theappended claims and that the materials and finish of the several partsemployed may be such as the experience or judgment of the manufacturermay dietate or varying conditions or uses may demand.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

1. In a pencil having a barrel section and a point section at itsforward end with a lead-receiving passage formed therein, an anchormember secured in the rear end of the barrel, a nut within the barrel, atubular extension on the nut extending through the anchor member andbeing rotatable therein, a threaded rod extending through the nut andinto the tubular extension, cooperating means on said threaded rod andthe barrel securing the threaded rod against rotation with relation tothe barrel, a pusher rod forming an extension of the threaded rod andextending into the lead-receiving passage, and means fixed on the outerend of the tubular extension to rotate the tubular extension and the nutto advance or retract the threaded rod and the pusher rod.

2. In a pencil having a barrel section and a point section at itsforward end with a lead-receiving passage formed therein, an anchormember secured in the rear end of the barrel, a nut within the barrel, atubular extension on the nut extending through the anchor member andbeing rotatable therein, a threaded rod extending through the nut andinto the tubular member, cooperating means on said threaded rod and thebarrel securing the threaded rod against rotation with relation to thebarrel, a pusher rod forming an extension on the threaded rod andextending into the lead-receiving passage, and a cap fixed on the outerend of the tubular extension to rotate the tubular extension and the nutto advance or retract the threaded rod and the pusher rod connectedtherewith.

3. In a pencil having a barrel section and a point section at itsforward end with a lead-receiving passage formed therein, a collaranchored in the rear end of the barrel, a nut within the barrel, atubular extension on the nut, a reduced end on said tubular extension, ashoulder formed between the reduced end and th tubular member, saidreduced end extending through the collar and being freely rotatabletherein, said shoulder engaging the inner end of the collar, a threadedrod extending through the nut and into the tubular extension,cooperating means on said threaded rod and the barrel securing thethreaded rod against rotation with relation to the barrel, a pusher rodforming an extension of the threaded rod and extending into thelead-receiving passage, and means fixed on the reduced end of thetubular extension to rotate the tubular extension and nut to advance orretract the threaded rod and the pusher rod connected therewith.

4. In a pencil having a barrel section and a point section at itsforward end with a leadreceiving passage formed therein, a collaranchored in the rear end of the barrel, a nut within the barrel, atubular extension on the nut, a reduced end on said tubular extension, ashoulder formed between the reduced end and the tubular member, saidreduced end extending through the collar and being freely rotatabletherein, said shoulder engaging the inner end of the collar, a threadedrod extending through the nut and into the tubular extension,cooperating means on said threaded rod and the barrel securing thethreaded rod against rotation with relation to the barrel, a pusher rodforming an extension of the threaded rod and extending into thelead-receiving passage, a cap fixed on the reduced end of the tubularextension to rotat the tubular extension and nut to advance or retractthe threaded rod and the pusher rod connected therewith, and a springbetween said collar and said cap for urging said shoulder against saidcollar.

5. In a pencil having a barrel section and. a point section at itsfoward end with a lead-.receiving passage formed therein, an anchor membersecured in the rear end of the barrel, a. nut within the barrel, atubular extension on the nut extending through the anchor member andbeing rotatable therein, a threaded rod extending through the nut andinto the tubular extension, cooperating means onsaid threaded rod andthebarrel securing the threaded rod against rotation with relation to thebarrel, a pusher rod forming an extension on the threaded rod andextending into the lead-receiving passage, a cap fixed on the outer endof the tubular extension to rotate the tubular extension and the nut toadvance or retract the threaded rod and the pusher rod connectedtherewith, and means 19. imposing friction to resist rotation of the capand connected members with respect to said anchor member.

6. In a pencil having a barrel section and a point section at itsforward end with a lead-receiving passage formed therein, a collaranchored in the rear end of the barrel, said collar having an annularrecess therein, a nut within the bar.- rel, a tubular extension on thenut, a reduced end on said tubular extension, a shoulder formed betweenthe reduced end and the tubular member, said reduced end extendingthrough the. collar and being freel rotatable therein, said shoulderengaging the inner end of the collar, a threaded rod extending throughthe nut and into the tubular extension, cooperating means on saidthreaded rod and the barrel securing the threaded rod against rotationwith relation to the barrel, a pusher rod forming an extension of thethreaded rod and extending into the lead-receiving passage, and a capfixed on the reduced end of the, tubular extension to rotate the tubularextension and nut to advance or retract the threaded rod and the pusherrod connected therewith, and a spring in said annular recess interposedbetween the cap and the collar, said spring impose ing friction toresist rotation of the cap and connected members with respect to saidcollar.

CHARLES E. WEHN.

REFERENCES CITED The following-references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,319,039 Bergen Oct. 21, 19191,540,920 Berryman June 9, 192:5 2,287,3651 Wehn June 23, 1942

